Shrinking Thermokarst Ponds and Groundwater Dynamics in Discontinuous Permafrost Near Council, Alaska
The purpose of this study was to characterize the geomorphological processes controlling the dynamics of ponds and to identify and characterize groundwater infiltration and surface water dynamics for a tundra terrain located in discontinuous permafrost near Council, Alaska. Thermokarst processes and...
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| Format: | Text |
| Language: | English |
| Published: |
2003
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.217.7000 http://nrm.salrm.uaf.edu/~dverbyla/nrm641/readings/Shrinking_Themokarst_Ponds.pdf |
| Summary: | The purpose of this study was to characterize the geomorphological processes controlling the dynamics of ponds and to identify and characterize groundwater infiltration and surface water dynamics for a tundra terrain located in discontinuous permafrost near Council, Alaska. Thermokarst processes and permafrost degradation were studied, focusing upon the interaction between surface and groundwater systems via an open talik. Synthetic aperture radar (SAR) data were used for classification of terrain units and surface water properties, while historical aerial photographs and satellite images (IKONOS) were used for assessment of pond shrinking and recent thermokarst progression. Geophysical surveys (ground penetrating radar and DC resistivity) were conducted to detect permafrost thickness and talik formations. Temperature boreholes and hydrological observation wells were monitored throughout the year and provided ground truth for validation of remotely-sensed data and geophysical surveys. Field and laboratory analyses enabled quantitative determination of subsurface hydrologic and thermal properties. We found many areas where alluvium deposits and ice-wedge polygonal terrain had developed thermokarst features within the last 20 years. Thermokarst ponds located over ice-wedge terrain have decreased in surface area since at least the early 20th Century. Small |
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